Factors Influencing Flood Risk

The video discusses how urbanization, deforestation, and channel modifications affect flood risk in a drainage basin. It explains the impact of these factors on hydrographs, highlighting changes in peak discharge and lag time. Urbanization and deforestation increase surface runoff, leading to higher flood magnitudes. Climate change exacerbates these effects by increasing precipitation levels, challenging existing infrastructure. Channel modifications, such as straightening and levees, can worsen flooding by increasing discharge within channels.

What are the main factors discussed that affect flood risk in a drainage basin?

• Industrial pollution and waste management

• Climate change and global warming

• Agricultural practices and soil erosion

• Urbanization, deforestation, and channel modifications

How does urbanization affect the peak discharge and lag time in a hydrograph?

• Increases peak discharge and decreases lag time

• Increases both peak discharge and lag time

• Decreases peak discharge and increases lag time

• Has no effect on peak discharge and lag time

What is the impact of deforestation on surface runoff?

• Has no impact on surface runoff

• Decreases surface runoff

• Increases surface runoff

• Only affects surface runoff during heavy rainfall

How do impermeable surfaces contribute to flood risk?

• They only affect surface runoff in urban areas

• They have no effect on surface runoff

• They increase surface runoff

• They decrease surface runoff

What role does climate change play in affecting flood risk?

• It can lead to unexpectedly large levels of precipitation

• It has no impact on flood risk

• It only affects flood risk in coastal areas

• It reduces the frequency of floods

How does urbanization lead to a steeper rising limb in hydrographs?

• By increasing the rate at which water builds up in the channel

• By decreasing the rate at which water builds up in the channel

• By having no effect on the rate of water buildup

• By only affecting the rate during heavy rainfall

What is the effect of channel straightening on flood events?

• It only affects flood events in rural areas

• It has no impact on flood events

• It always prevents floods

• It can lead to adverse effects

How can building artificial levees on river banks affect flood risk?

• It can increase discharge in the channel

• It always reduces flood risk

• It has no impact on flood risk

• It only affects flood risk during storms

What is the potential impact of channel modifications on flood magnitude?

• They can exacerbate flood magnitude

• They have no impact on flood magnitude

• They always reduce flood magnitude

• They only affect flood magnitude in urban areas

Which of the following is NOT a factor discussed that affects flood risk?

• Channel modifications

• Deforestation

• Urbanization

• Industrial pollution